As the speaker (the young man) in Wadsworth Longfellow’s poem ‘A Psalm of Life’ says it, we should not trust our future however pleasant it may look at present. Even if it looks very bright now, situations may change later. In short, we can never be certain of our future and so we should not trust it. Rather we have to work in the present to make our life a success.

Again, past is past. We should not be worried or even happy thinking of our past failures or successes. Past should be forgotten and utmost concentration should be given on our present situation and the works we have in hand. This is how the poet expresses it —

Trust no Future, howe’er pleasant!
Let the dead Past bury its dead!
Act, — act in the living Present!